Method and apparatus for manufacturing semi-solidified metal

ABSTRACT

A predetermined amount of molten metal  12  is supplied to a heat-insulating crucible  18 . After that, a chill block  46 , which is cooled to a predetermined temperature of not more than a temperature of the molten metal  12 , is immersed and rotated in the molten metal  12 . Accordingly, the molten metal  12  is agitated while being cooled to give no directivity of cooling. It is possible to obtain semisolidified metal  20  which is formed into slurry uniformly and effectively as a whole. The semisolidified metal  20  is discharged from the heat-insulating crucible  18 , and it is supplied to a forming machine  22  to apply a forming treatment thereto. Accordingly, it is possible to produce the desired slurry efficiently and economically.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/JP99/00163 which has an Internationalfiling date of Jan. 19, 1999, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a method and an apparatus for producingsemisolidified metal to obtain predetermined slurry from molten metal.

BACKGROUND ART

An operation is generally performed to produce semisolidified metal,i.e., slurry in an amount of one shot for the forming process, by usingmolten metal of, for example, aluminum, magnesium, or alloy thereof. Itis known that a forming operation based on the use of slurry especiallyhas such an advantage that the surface accuracy of a formed product isexcellent. In order to produce such slurry, for example, thethixocasting process and the rheocasting process are widely adopted.

However, in the case of the thixocasting process described above, it isnecessary to use an exclusive billet and a reheating apparatus. For thisreason, the following problems are pointed out. That is, the materialcost and the equipment cost are considerably expensive, and the entireproduction operation is complicated.

On the other hand, in the rheocasting process, the mass production isperformed based on the continuous batch system. In this process, thecooling is performed by discharging the molten metal while allowing themolten metal to make contact with a cooling section cooled with water.Therefore, the temperature of slurry differs between the start and theend of the cooling. A problem arises in that the temperature of theslurry is not managed accurately.

A method is also known, in which slurry is produced in accordance withcooling, heating, and agitation in a forming machine. However, thefollowing inconveniences arise. That is, the cycle time is prolonged,and especially the shot weight is increased.

When the produced slurry is supplied into the forming machine, acontainer for accommodating the, slurry is usually inverted in thevertical direction. However, it is difficult to discharge the entireamount of slurry in the container, for example, due to the temperatureof the slurry in the container, the shape of the container, and theweight of the slurry. As a result, the following problems are pointedout. That is, remaining matters of the slurry appear in the container,and the supply weight of the slurry is dispersed. Further, the slurry,which:is newly produced in the container, is badly affected thereby.

When different parts are formed, the shot weight differs dependingthereon. Therefore, the following problems are pointed out. That is, itis impossible to correctly manage the temperature of the slurry. Whenthe shot weight is increased, it takes a long time to perform theoperation for producing the slurry. It is difficult to efficientlyperform the forming operation for a variety of different parts to givehigh qualities.

An object of the present invention is to provide a method and anapparatus for producing semisolidified metal, which make it possible toproduce desired slurry efficiently and economically.

Another object of the present invention is to provide an apparatus forproducing semisolidified metal, which makes it possible to economicallyproduce desired slurry and easily discharge the slurry in a reliablemanner.

Still another object of the present Invention is to provide an apparatusfor producing semisolidified metal, which makes it possible toeconomically produce various slurries having different weight so thatthey have high qualities, wherein the system is simplified.

DISCLOSURE OF THE INVENTION

According to the present invention, a predetermined amount of moltenmetal is supplied to a heat-insulating crucible. After that, the moltenmetal in the crucible is cooled by the aid of a cooling member which iscooled to be at a predetermined temperature of not more than atemperature of the molten metal. Simultaneously, the molten metal isagitated. Accordingly, in the heat-insulating crucible, the molten metalis reliably formed into slurry generally uniformly as a whole withoutinvolving any directivity of cooling. Thus, the reheating isunnecessary, and it is possible to efficiently obtain desiredsemisolidified metal.

According to the present invention, a predetermined amount of moltenmetal is supplied to a heat-insulating crucible, and then the moltenmetal in the crucible is cooled by the aid of a cooling member which iscooled to be at a predetermined temperature of not more than atemperature of the molten metal. Further, the cooling member is moved inthe horizontal direction and/or in the vertical direction while rotatingthe cooling member. Thus, the molten metal is agitated. For example, thecooling member is moved in a reciprocating manner in the horizontaldirection and/or in the vertical direction. Alternatively, the coolingmember is moved spirally in the horizontal direction.

Accordingly, especially when heat-insulating crucibles having variousshapes are used, the cooling member is moved along with the shape of theheat-insulating crucible. Thus, the directivity of cooling is excludedto be as less as possible, and the molten metal can be effectivelyagitated. Accordingly, the molten metal is formed into slurry uniformlyand reliably as a whole. It is possible to obtain desired semisolidifiedmetal efficiently with a high quality.

In the present invention, the semisolidified metal is produced after apredetermined amount of molten metal is supplied to a heat-insulatingcrucible, by cooling and agitating the molten metal in theheat-insulating crucible by the aid of a plurality of cooling members.Accordingly, even when the shot weight is increased, then thedirectivity of cooling is avoided to be as less as possible, and it ispossible to quickly and smoothly obtain the desired semisolidified metalformed into slurry uniformly and reliably as a whole.

Further, the cooling members are integrally held by a driving mechanismby the aid of a fixing means in a state in which an arbitrary number ofthe cooling members are stacked with each other. Therefore, it is enoughto change the number of stacked cooling members depending on the changeof the shot weight. Thus, it is possible to produce the desiredsemisolidified metal efficiently to have a high quality. The fixingmeans includes a shaft member for being integrally inserted into theplurality of stacked cooling members, and a fixture for being screwed onan end of the shaft member. Thus, it is possible to effectively simplifythe structure.

In the present invention, the molten metal is supplied into aheat-insulating crucible, and then a cooling member is immersed in themolten metal. The molten metal is agitated in a state in which a coolingmedium having a predetermined temperature is supplied to the inside ofthe cooling member. Accordingly, the directivity of cooling is avoidedto be as less as possible, and it is possible to convert the moltenmetal into slurry quickly and reliably. Further, when the temperature ofthe cooling medium is managed, it is unnecessary to reheat thesemisolidified metal. Thus, it is possible to efficiently obtain thedesired semisolidified metal.

In the present invention, a predetermined amount of molten metal issupplied to divided type heat-insulating crucibles. After that, themolten metal in the heat-insulating crucibles is cooled and agitated bythe aid of a cooling member to produce semisolidified metal.Subsequently, the heat-insulating crucibles are subjected toopening/closing operation by the aid of an opening/closing mechanism.Accordingly, the semisolidified metal in the heat-insulating cruciblesfalls in accordance with its self-weight, and it is discharged from theheat-insulating crucibles.

Accordingly, the directivity of cooling is avoided to be as less aspossible, and it is possible to obtain the desired semisolidified metalformed into slurry uniformly and reliably as a whole. Further, it ispossible to discharge the semisolidified metal from the heat-insulatingcrucibles smoothly and reliably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an illustrative schematic perspective view depicting aproduction apparatus for carrying out a method for producingsemisolidified metal according to a first embodiment of the presentinvention.

FIG. 2 shows an illustrative plan view depicting the productionapparatus.

FIG. 3 illustrates the operation of a molten metal-ladling robot whichconstructs the production apparatus.

FIG. 4 illustrates an agitator which constructs the productionapparatus.

FIGS. 5A to 5E illustrate a chill block-treating unit for treating achill block which constructs the agitator.

FIG. 6 shows a time table for a mass production system based on the useof the production apparatus.

FIG. 7 illustrates the temperature change of each of portions in acrucible during the operation of the production apparatus.

FIG. 8 shows an illustrative perspective view depicting the operation ofthe production apparatus.

FIG. 9 shows an illustrative perspective view depicting the operation ofthe production apparatus.

FIG. 10 shows an illustrative schematic perspective view depicting aproduction apparatus for carrying out a method for producingsemisolidified metal according to a second embodiment of the presentinvention.

FIGS. 11A to 11F show steps illustrating the operation of the productionapparatus.

FIG. 12 shows an illustrative schematic perspective view depicting aproduction apparatus for carrying out a method for producingsemisolidified metal according to a third embodiment of the presentinvention.

FIGS. 13A to 13G show steps illustrating the operation of the productionapparatus.

FIG. 14 illustrates a chill block having a cylindrical configuration.

FIG. 15 illustrates a chill block having a bottom-equipped cylindricalconfiguration.

FIG. 16 shows an illustrative schematic perspective view depicting aproduction apparatus for carrying out a method for producingsemisolidified metal according to a fourth embodiment of the presentinvention.

FIG. 17 illustrates an agitator which constructs the productionapparatus.

FIG. 18 shows an illustrative schematic perspective view depicting theagitator.

FIG. 19 shows an illustrative schematic perspective view depicting anagitator which constructs a production apparatus for carrying out amethod for producing semisolidified metal according to a fifthembodiment of the present invention.

FIG. 20 shows an illustrative schematic perspective view depicting anagitator which constructs a production apparatus for carrying out amethod for producing semisolidified metal according to a sixthembodiment of the present invention.

FIG. 21 illustrates a chill block designed to have an external shape ofan elliptical configuration.

FIG. 22 illustrates a chill block designed to have an external shape ofa composite elliptical configuration.

FIG. 23 illustrates a chill block designed to have an external shape ofa chamfered rectangular configuration.

FIG. 24 illustrates a chill block designed to have an external shape ofa hexagonal configuration.

FIG. 25 illustrates a chill block designed to have an external shape ofa chamfered hexagonal configuration.

FIG. 26 shows an illustrative schematic perspective view depicting anapparatus for producing seimsolidified metal according to a seventhembodiment of the present invention.

FIG. 27 illustrates an agitator which constructs the productionapparatus.

FIG. 28 illustrates, in cross section, chill blocks which construct theagitator.

FIG. 29 shows an illustrative schematic perspective view depicting anapparatus for producing semisolidified metal according to an eighthembodiment of the present invention.

FIG. 30 illustrates a chill block which constructs an apparatus forproducing semisolidified metal according to a ninth embodiment of thepresent invention.

FIG. 31 shows an illustrative schematic view, with partial crosssection, depicting an apparatus for producing semisolidified metalaccording to a tenth embodiment of the present invention.

FIG. 32 illustrates a magnified view depicting a cooling member whichconstructs the production apparatus.

FIG. 33A illustrates a step of supplying molten metal to a crucible.

FIG. 33B illustrates a step of raising the crucible to immerse thecooling member in the molten metal.

FIG. 33C illustrates a step of supplying first liquid metal to thecooling member to cool and agitate the molten metal.

FIG. 33D illustrates a step of supplying second liquid metal to thecooling member after the semisolidified metal is produced.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows an illustrative schematic perspective view is depicting aproduction apparatus 10 for carrying out a method for producingsemisolidified metal according to the first embodiment of the presentinvention, and FIG. 2 shows an illustrative plan view depicting theproduction apparatus 10.

The production apparatus 10 comprises a molten metal-holding furnace 14for holding molten metal 12 which is composed of melted metal such asaluminum, alloy thereof, magnesium, and alloy thereof; a moltenmetal-ladling robot 16 for ladling a predetermined amount (amount forone shot) of the molten metal 12 from the molten metal-holding furnace14; a supply robot 26 for pouring the molten metal 12 ladled by themolten metal-ladling robot 16 into a predetermined heat-insulatingcrucible 18, and supplying semisolidified metal 20 formed into a desiredslurry state in the crucible 18 to a slurry-introducing port 24 whichcommunicates with an unillustrated cavity of a forming machine 22; andfirst to fourth agitators 28 a to 28 d each of which is arranged for thecrucible 18 for cooling and agitating the molten metal 12 in thecrucible 18.

As shown in FIGS. 1 and 3, the molten metal-ladling robot 16 includes anarm 32 which is provided swingably on a support pillar 30. A ladle 34 isinstalled tiltably to the forward end of the arm 32. The supply robot 26is movable back and forth along a rail 36 which extends in a direction(direction of the arrow A) of arrangement of the first to fourthagitator 28 a to 28 d. The supply robot 26 is an articulated type robot,and it has, at its forward end, a gripping section 38 capable of holdingthe heat-insulating crucible 18.

The first agitator 28 a includes a crucible holder 40 on which thecrucible 18 is detachably arranged. As shown in FIG. 4, the crucibleholder 40 is provided with a recess 42 for accommodating the crucible18. A heater 44 is embedded at the inside of the crucible holder 40 sothat the heater 44 circumscribes the crucible 18 arranged in the recess42.

A chill block (cooling member) 46, which also has an agitating function,is detachably arranged with a driving mechanism 48 at a position overthe crucible holder 40. The chill block 46 is made of, for example, amaterial such as copper and stainless steel which is not melted at themolten temperature of aluminum molten metal to be used as the moltenmetal 12. The external shape of the chill block 46 is designed to have acolumnar configuration, with a draft sloped downwardly.

The chill block 46 is detachable with respect to a driving mechanism 48by the aid of a coupler 49 made of ceramics. The driving mechanism 48 ismoved upwardly and downwardly over the crucible holder 40, and it drivesand rotates the chill block 46.

The second to fourth agitators 28 b to 28 d are constructed in the samemanner as the first agitator 28 a described above. The same constitutivecomponents are designated by the same reference numerals, detailedexplanation of which will be omitted.

Each of the chill blocks 46 is detachable with respect to each of thedriving mechanisms 48 provided for the first to fourth agitators 28 a to28 d. The chill block 46 is detached from the driving mechanism 48 everytime when the molten metal 12 is agitated and cooled (for every oneshot), and it is fed to a chill block-treating unit 50.

As shown in FIGS. 5A to 5E, the chill block-treating unit 50 comprises acooling tank 52 for cooling the chill block 46 disengaged from thedriving mechanism 48 with a cooling medium such as cooling oil; an airblow means 54 for effecting air blow against the chill block 46 afterthe cooling to remove solidified matters of aluminum from the surface; acoating tank 56 for immersing the chill block 46 after the air blow in acoating liquid composed of a ceramic material; and a drying means 60 fordrying the chill block 46 after the coating with a heater 58.

The operation of the production apparatus 10 constructed as describedabove will be explained below. FIG. 6 shows a time table for the massproduction system based on the use of the production apparatus 10.

At first, the molten metal-ladling robot-16 is operated in a state inwhich the molten metal 12 is heated and maintained at about 650° C. inthe molten metal-holding furnace 14. As shown in FIG. 3, the moltenmetal-ladling robot 16 is operated as follows. That is, the ladle 34 isinserted into the molten metal-holding furnace 14 in accordance with theaction of the arm 32. The ladle 34 is inclined or tilted, so that themolten metal 12 in an amount of one shot is ladled by the ladle 34. Theladle 34, which has ladled the molten metal 12, is moved to a pouringposition (see the position depicted by two-dot chain lines in FIG. 3).On the other hand, the supply robot 26, which holds the empty crucible18, is arranged at the pouring position by the aid of the grippingsection 38 (see FIG. 1).

In this situation, the ladle 34 is tilted, and the molten metal 12 inthe amount of one shot is poured into the crucible 18 held by the supplyrobot 26. Subsequently, the supply robot 26 inserts the crucible 18 at apredetermined position of each of the first to fourth agitators 28 a to28 d, for example, into the recess 42 of the crucible holder 40 whichconstitutes the first agitator 28 a. The heater is operated in thecrucible holder 40 to maintain a predetermined temperature beforehand.The molten metal 12 in the crucible 18 arranged in the recess 42 isprevented from being cooled all at once by the surroundings.

In the first agitator 28 a, the chill block 46 is previously heated andmaintained at about 100° C. in order to remove any moisture andstabilize the cooling condition. The chill block 46 is immersed in themolten metal 12 in the crucible 18 while being rotated in apredetermined direction at a relatively low speed by the aid of thedriving mechanism 48. After that, the rotation speed of the chill block46 is increased in the molten metal 12 in accordance with the action ofthe driving mechanism 48. Thus, the molten metal 12 is quickly agitatedwhile being cooled.

After the chill block 46 agitates the molten metal 12 for a presetperiod of time or until a slurry,supply signal is inputted, the chillblock 46 is raised and withdrawn from the crucible 18 while beingrotated. Accordingly, the semisolidified metal 20, which is maintainedto have a constant temperature as a whole, is obtained in theheat-insulating crucible 18.

Changes occur as shown in FIG. 7 in the steps for producing thesemisolidified metal 20 described above, concerning the atmosphere inthe crucible 18, the temperature of the crucible 18, the centertemperature of the molten metal 12, the end temperature of the moltenmetal 12, and the temperature of the chill block 46.

On the other hand, the supply robot 26 is moved, for example,corresponding to the fourth agitator 28 d which possesses thesemisolidified metal 20 cooled and agitated to give a desired slurrystate, of the first to fourth agitators 28 a to 28 d. In the fourthagitator 28 d, the driving mechanism 48 waits at an upward position, andthe chill block 46 is removed. The supply robot 26 grips the crucible 18which is arranged on the crucible holder 40 of the fourth agitator 28 d,and it takes the crucible 18 out of the fourth agitator 28 d (see FIG.8).

The supply robot 26 is further operated such that the crucible 18, whichis gripped by the gripping section 38, is arranged with respect to theslurry-introducing port 24 of the forming machine 22, and then thecrucible 18 is inverted. Accordingly, the semisolidified metal 20 in thecrucible 18 is allowed to fall so that it falls to be supplied to theslurry-introducing port 24 (see FIG. 9). In the forming machine 22, theforming process is performed with the semisolidified metal 20 to obtaina predetermined formed product.

The supply robot 26 moves the empty crucible 18 to the air blow positionto apply the air blow treatment thereto. Accordingly, any aluminum,which remains in the heat-insulating crucible 18, is removed.Subsequently, the inside of the crucible 18 is subjected to coating witha ceramic material or the like, and then the crucible 18 is arranged atthe pouring position.

In the first agitator 28 a, the chill block 46, which is retractedupwardly after performing the cooling and the agitation for the moltenmetal 12, is disengaged from the driving mechanism 48, and it istransported to the chill block-treating unit 50 by the aid of a robot orthe like (see FIG. 5A). In the chill block-treating unit 50, as shown inFIG. 5B, the chill block 46 is firstly immersed in the cooling tank 52to perform the cooling treatment. After that, the air blow means 54 isused to remove aluminum solidified matters adhered to the surface of thechill block 46 (see FIG. 5C). Further, as shown in FIG. 5D, the chillblock 46 is immersed in a coating liquid in the coating tank 56 to coatthe surface thereof with a ceramic material, because of the followingreason. That is, the surface of the chill block 46 is prevented from anyreaction with the molten metal 12, and it is easy to remove aluminumsolidified matters adhered to the surface of the chill block 46.

The chill block 46 after the coating treatment is subjected to thedrying treatment in accordance with the action of the heater 58 whichconstitutes the drying means 60. The chill block 46 is heated to apredetermined temperature (see FIG. 5E). After the drying, the chillblock 46 is installed to the driving mechanism. 48, and it is used againto perform the cooling and agitating operations for the new molten metal12.

In the first embodiment of the present invention, the molten metal 12 inthe crucible 18 is cooled by using the chill block 46 which ismaintained at the temperature lower than the temperature of the moltenmetal 12. The chill block 46 is rotated to effect the agitation.Accordingly, no directivity occurs during the cooling of the moltenmetal 12. It is possible to obtain the semisolidified metal 20 formedinto the slurry uniformly and reliably as a whole. It is possible tosupply the semisolidified metal 20 to the slurry-introducing port 24 ofthe forming machine 22 without heating the semisolidified metal 20again.

As a result, it is possible to always obtain the stable semisolidifiedmetal 20 for every one shot. Further, it is unnecessary to provide anyequipment such as the reheating apparatus. Accordingly, the effect canbe obtained such that it is possible to produce the semisolidified metal20 economically and efficiently. Further, the external shape of thechill block 46 is designed to have the columnar configuration. It ispossible to effectively prevent the chill block 46 from beingdeteriorated by the molten metal 12 formed into the slurry. The chillblock 46 has the draft which is sloped downwardly. Accordingly, it ispossible to smoothly withdraw the chill block 46 from the semisolidifiedmetal 20.

In the first embodiment, the air blow means 54 is used to remove thealuminum solidified matters adhered to the surface of the chill block46. However, in place of the air blow means 54, it is possible to use,for example, a vibration-generating means and a sandblast means.

In the first embodiment, the molten metal-ladling robot 16 for ladlingthe molten metal in the amount of one shot is provided between themolten metal-holding furnace 14 and the supply robot 26. However, it isnot necessarily indispensable to use the molten metal-lading robot 16provided that the apparatus is constructed such that the molten metal 12in the amount of one shot is directly fed from the molten metal-holdingfurnace 14 to the crucible 18 held by the supply robot 26.

FIG. 10 shows an illustrative schematic perspective view depicting aproduction apparatus 70 for carrying out a method for producingsemisolidified metal according to the second embodiment of the presentinvention.

The production apparatus 70 comprises divided type crucibles 80 a, 80 b;divided type crucible holders 82 a, 82 b for accommodating the crucibles80 a, 80 b; a molten metal-feeding means 86 for feeding molten metal 84into the crucibles 80 a, 80 b; an agitator 88 for cooling and agitatingthe molten metal 84 in the crucibles 80 a, 80 b; and a supply robot 92for integrally holding the crucibles 80 a, 80 b to take them out of thecrucible holders 82 a, 82 b, and feeding semisolidified metal 90 to theforming machine 22.

The crucibles 80 a, 80 b are constructed by dividing a bottom-equippedcylinder into two in the diametral direction. A pair of hook-shapedprojections 94 a, 94 b and a pair of grooves 96 a, 96 b are arrangedlinearly in the axial direction on the outer circumferences of thecrucibles 80 a, 80 b respectively (see FIG. 11A). A heat-resistancepacking 97 is interposed between joining surfaces of the crucibles 80 a,80 b.

As shown in FIG. 11A, the crucible holders 82 a, 82 b are constructed bydividing a bottom-equipped cylinder into two in the diametral direction.The crucible holders 82 a, 82 b are swingably supported at supportingpoints 98 a, 98 b of their respective lower end angular portions withrespect to an installation plane 99. Rods 102 a, 102 b, which extendfrom cylinders 100 a, 100 b, are connected to side portions of thecrucible holders 82 a, 82 b, while the cylinders 100 a, 100 b aretiltable with respect to the installation plane 99.

When the crucible holders 82 a, 82 b are closed, a recess 104 isintegrally formed therein. Heaters 106 a, 106 b are embedded tocircumscribe the recess 104.

As shown in FIG. 10, the molten metal-feeding means 86 is provided witha ladle 108 for ladling the molten metal 84 in an amount of one shotfrom the molten metal-holding furnace 14. The ladle 108 is constructedtiltably and movably between the ladling position for the molten metal84 and the pouring position for the crucibles 80 a, 80 b.

The agitator 88 is provided with a chill block (cooling member) 110which is made of, for example, stainless steel. The external shape ofthe chill block 110 is designed to have a columnar configuration. Thechill block 110 is rotatable and movable upwardly and downwardly by theaid of an unillustrated driving mechanism. The chill block 110 isinserted rotatably into a lid member 112. The lid member 112 is movableupwardly and downwardly in an integrated manner together with the chillblock 110. It is desirable that the lid member 112 is made of a materialhaving no gas permeability. The surface, which makes contact with themolten metal 84, is designed to be a planar surface or to have a conicalor pyramidal configuration protruding toward the molten metal 84 at itscentral portion.

The supply robot 92 is provided with a wrist section 114. Anopening/closing mechanism 115 is installed to the wrist section 114. Theopening/closing mechanism 115 has cylinders 116 a, 116 b which serve asforward/backward moving means. Ends of arm members 120 a, 120 b disposedvertically downwardly are secured to rods 118 a, 118 b which extend inmutually opposite directions from the cylinders 116 a, 116 b. The armmembers 120 a, 120 b are provided with a pair of outer projections 122a, 122 b which are inserted into and engaged with the respectiveprojections 94 a, 94 b of the crucibles 80 a, 80 b, and a pair of innerprojections 124 a, 124 b which are fitted to the grooves 96 a, 96 b ofthe crucibles 80 a, 80 b.

A lid member 126, which is positioned under the opening/closingmechanism 115 and which is made of a heat-insulating material, issecured to the supply robot 92. The lid member 126 makes tight contactwith the upper surfaces of the crucibles 80 a, 80 b to ensure theheat-insulating performance of the crucibles 80 a, 80 b when thecrucibles 80 a, 80 b are held by the arm members 120 a, 120 b. The lidmember 126 also functions to avoid any leakage of the semisolidifiedmetal 90.

In the second embodiment constructed as described above, the crucibles80 a, 80 b are firstly inserted between the crucible holders 82 a, 82 bin a state in which the crucible holders 82 a, 82 b are mutually open tostand on the supporting points 98 a, 98 b as shown in FIG. 11A.Subsequently, the cylinders 100 a, 100 b are operated to displace therods 102 a, 102 b frontwardly respectively. Accordingly, the crucibleholders 82 a, 82 b make swinging movement in directions to make approachto one another. Therefore, the crucibles 80 a, 80 b are accommodated inthe recess 104 which is formed integrally between the crucible holders82 a, 82 b. In this arrangement, the size of the recess 104 is designedto be slightly smaller than the external shape of the crucibles 80 a, 80b. The crucibles 80 a, 80 b are held in a liquid-tight manner with eachother with the heat-resistance packings 97 intervening therebetween in astate in which the crucible holders 82 a, 82 b are mutually closed.

Subsequently, as shown in FIG. 11B, the ladle 108, which constitutes themolten metal-feeding means 86, ladles the molten metal 84 in the amountof one shot, and the molten metal 84 is fed into the crucibles 80 a, 80b. The crucibles 80 a, 80 b are heated and held at a predeterminedtemperature (for example, 280° C.) by the aid of the heaters 106 a, 106b embedded in the crucible holders 82 a, 82 b. The molten metal 84,which is aluminum molten metal maintained at 650° C. to 700°0 C., is fedinto the crucibles 80 a, 80 b.

On the other hand, in the agitator 88, the chill block 110 is heated to100°0 C. in order to remove, for example, moisture. As shown in FIG.11C, the chill block 110 is moved downwardly from a position over thecrucibles 80 a, 80 b while being rotated. Accordingly, the chill block110 cools the molten metal 84 in the crucibles 80 a, 80 b, and itagitates the molten metal 84. More preferably, the chill block 110 isimmersed in the molten metal 84 in the crucibles 80 a, 80 b while beingrotated in a predetermined direction at a relatively low speed. Afterthat, the rotation speed of the chill block 110 is increased in themolten metal 84. Accordingly, the chill block 110 quickly agitates themolten metal 84 while cooling the molten metal 84.

During this process, the lid member 112 is moved downwardly integrallywith the chill block 110. The lid member 112 is arranged on the openupper end side of the crucibles 80 a, 80 b. Accordingly, the surface ofthe molten metal 84 is not oxidized during the cooling and the agitationeffected by the chill block 110. Further, it is possible to reliablyavoid any contamination of air into the molten metal 84.

The cooling and the agitation are performed for a predetermined periodof time to obtain the semisolidified metal 90 in a desired slurry state.After that, the chill block 110 is taken out of the crucibles 80 a, 80 bwhile being rotated. On the other hand, the supply robot 92 is arrangedover the crucibles 80 a, 80 b. The supply robot 92 is operated such thatthe arm members 120 a, 120 b are moved downwardly by the aid of thewrist section 114 (see FIG. 11D). The respective outer projections 122a, 122 b are fitted to the projections 94 a, 94 b of the crucibles 80 a,80 b. The respective inner projections 124 a, 124 b are fitted to thegrooves 96 a, 96 b of the crucibles 80 a, 80 b.

Subsequently, as shown in FIG. 11E, the crucible holders 82 a, 82 b makeswinging movement in directions to make separation from each other inaccordance with the action of the cylinders 100 a, 100 b. The crucibles80 a, 80 b, which have been held by the recess 104, are taken out in astate of being held by the arm members 120 a, 120 b. The wrist section114 is arranged at a position over the slurry-introducing port 24 of theforming machine 22. After that, the cylinder 116 a, 116 b, whichconstruct the opening/closing mechanism 115, are operated to displacethe rods 118 a, 118 b in directions to make separation from each other.

Therefore, the arm members 120 a, 120 b are displaced in directions tomake separation from each other. The crucibles 80 a, 80 b, which areheld by the arm members 120 a, 120 b, are released from each other. Thesemisolidified metal 90 is produced integrally in the crucibles 80 a, 80b. When the crucibles 80 a, 80 b are open, then the semisolidified metal90 falls, and it is supplied to the slurry-introducing port 24 (see FIG.11F).

As described above, in the second embodiment, the molten metal 84 in theamount of one shot, which is fed into the crucibles 80 a, 80 b, areagitated in accordance with the rotating action of the chill block 110while being cooled by the chill block 110. Accordingly, it is possibleto obtain the semisolidified metal 90 in a satisfactory slurry state,which has no directivity of cooling and which is uniform as a whole.Further, the open ends of the crucibles 80 a, 80 b are closed by the lidmember 112 during the cooling and the agitation effected by the chillblock 110. Therefore, it is possible to effectively avoid any oxidationof the surface of the molten metal 84 and any contamination of air intothe molten metal 84. Accordingly, such an effect is obtained that thesemisolidified metal 90 having a high quality can be efficientlyobtained.

The apparatus further includes the divided type crucibles 80 a, 80 b.The arm members 120 a, 120 b, which constitute the robot 92, are engagedwith the:crucibles 80 a, 80 b respectively so that the crucibles 80 a,80 b may be opened and closed. Accordingly, the semisolidified metal 90is reliably allowed to fall, and it can be easily supplied to theslurry-introducing port 24 merely by moving the crucibles 80 a, 80 b inthe directions to make separation from each other at the position overthe slurry-introducing port 24.

Therefore, in the second embodiment, the entire amount of thesemisolidified metal 90 can be reliably discharged from the crucibles 80a, 80 b with the simple arrangement without being affected, for example,by the temperature of the semisolidified metal 90 in the crucibles 80 a,80 b, the shape of the crucibles 80 a, 80 b, and the weight of thesemisolidified metal 90. Accordingly, the supply weight of thesemisolidified metal 90 is not dispersed, which would be otherwisecaused by the occurrence of any remaining matter of the semisolidifiedmetal 90 in the crucibles 80 a, 80 b. Further, such an effect isobtained that it is possible to effectively prevent the semisolidifiedmetal 90 to be newly produced in the crucibles 80 a, 80 b from beingbadly affected.

FIG. 12 shows an illustrative schematic perspective view depicting aproduction apparatus 130 for carrying out a method for producingsemisolidified metal according to the third embodiment of the presentinvention.

The production apparatus 130 comprises divided type crucibles 140 a, 140b; divided type crucible holders 142 a, 142 b; a robot 144 fortransporting the crucibles 140 a, 140 b; a molten metal-feeding means148 for feeding molten metal 146 in an amount of one shot into thecrucibles 140 a, 140 b; and an agitator 150 for cooling and agitatingthe molten metal 146 in the crucibles 140 a, 140 b.

A pair of projections 152 a, 152 b are formed to expand on outercircumferential portions of the crucibles 140 a, 140 b. The crucibleholder 142 a is connected to a rod 158 which extends from a cylinder156, and it is movable back and forth in directions of the arrow by theaid of a pulley 160. The crucible holder 142 b is fixed to aninstallation plane 161. When the crucible holders 142 a, 142 b aremutually closed, a recess 162 is integrally formed therein. Heaters 164a, 164 b are embedded in the crucible holders 142 a, 142 b respectively(see FIG. 13A).

An opening/closing mechanism 166 is installed to the robot 144. Upperends of arm members 172 a, 172 b are connected to rods 170 a, 170 bwhich extend from cylinders 168 a, 168 b for constructing theopening/closing mechanism 166. Fastening means 174 a, 174 b, which areused to make engagement with the projections 152 a, 152 b provided onthe side surfaces of the crucibles 140 a, 140 b, are provided on lowerend sides of the arm members 172 a, 172 b.

The molten metal-feeding means 148 is provided with a ladle 176. Theagitator 150 is provided with a chill block 178 having a relativelysmall diameter. The chill block 178 is rotatable by the aid of a drivingmechanism 180. The driving mechanism 180 is installed to a movable base182, and it is movable in the direction of the arrow (in the horizontaldirection).

In the third embodiment constructed as described above, the operation isfirstly performed as shown in FIG. 13A. That is, in a state in which thecrucible holder 142 a is separated from the crucible holder 142 b, thecrucibles 140 a, 140 b are gripped by the robot 144, and they areinserted into the crucible holders 142 a, 142 b. Subsequently, thecrucible holder 142 a is moved toward the crucible holder 142 b to bemutually closed in accordance with the driving action of the cylinder156. The crucibles 140 a, 140 b are accommodated and held in the recess162 which is integrally formed therebetween (see FIG. 13B).

Further, as shown in FIG. 13C, the molten metal 146 in the amount of oneshot is fed into the crucibles 140 a, 140 b by the aid of the ladle 176which constitutes the molten metal-feeding means 148. After that, asshown in FIG. 13D, the agitator 150 is operated. In the agitator 150,the chill block 178, which is cooled at a predetermined temperature, isrotated by the aid of the driving mechanism 180 while being immersed inthe molten metal 146. The movable base 182 is moved back and forth inthe horizontal direction. Accordingly, the molten metal 146 in thecrucibles 140 a, 140 b is cooled and agitated to obtain thesemisolidified metal 184 having a desired slurry state.

Subsequently, as shown in FIG. 13E, the arm members 172 a, 172 b, whichconstruct the robot 144, enter the inside of the crucible holders 142 a,142 b to grip the crucibles 140 a, 140 b. After that, the crucibleholder 142 a is operated to be open in accordance with the action of thecylinder 156, while the robot 144 is moved upwardly (see FIG. 13F). Therobot 144 arranges the crucibles 140 a, 140 b corresponding to thepredetermined slurry-introducing port 24. When the arm members 172 a,172 b make swinging movement in directions to make separation from eachother in accordance with the action of the cylinders 168 a, 168 b, thenthe crucibles 140 a, 140 b mutually make swinging movement in openingdirections, and thus the semisolidified metal 184 falls to be suppliedto the slurry-introducing port 24 (see FIG. 13G).

Therefore, in the third embodiment, the same effect as that of thesecond embodiment is obtained by using the divided type crucibles 140 a,140 b.

In the first to third embodiments, the chill blocks 46, 110, 178 aredesigned to have the columnar configuration. However, it is enough thatat least the external shape has the columnar configuration. For example,a chill block 186 shown in FIG. 14 includes a cylindrical member 188,and an attachment plate 189 to which an end of the cylindrical member188 is secured. A chill block 190 shown in FIG. 15 includes abottom-equipped cylindrical member 192, and a shaft member 194 which issecured to an inner bottom portion 192 a of the cylindrical member 192.

FIG. 16 shows an illustrative schematic perspective view depicting aproduction apparatus 200 for carrying out a method for producingsemisolidified metal according to the fourth embodiment of the presentinvention. The same constitutive components as those of the productionapparatus 70 according to the second embodiment shown in FIG. 10 aredesignated by the same reference numerals, detailed explanation of whichwill be omitted.

The production apparatus 200 is provided with an agitator 202. As shownin FIGS. 16 and 17, a chill block (cooling member) 204, which constructsthe agitator 202, is detachably arranged with respect to a rotarysection 206 with a coupler 208 made of ceramics interveningtherebetween, at a position over crucible holders 82 a, 82 b. The chillblock 204 is composed of, for example, a material such as copper andstainless steel which is not melted at a melting temperature of aluminummolten metal to be used as the molten metal 84. The external shape ofthe chill block 204 is designed to have a quadratic prism-shapedconfiguration, with a draft formed downwardly.

The rotary section 206 rotates and drives the chill block 204. Therotary section 206 is constructed to be movable upwardly and downwardlyin an integrated manner together with the chill block 204 by the aid ofa moving section 210, and it is moved along a spiral configuration inthe horizontal direction (see FIG. 18). That is, the moving section 210has two functions of an elevator means and a spiral movable means. Adriving mechanism is constructed by the rotary section 206 and themoving section 210.

As shown in FIG. 18, in the production apparatus 200 according to thefourth embodiment constructed as described above, the molten metal 84 inthe crucibles 80 a, 80 b is cooled by the chill block 204 which ismaintained at a temperature lower than the temperature of the moltenmetal 84. The molten metal 84 is agitated by moving the chill block 204in the spiral configuration in the horizontal direction along the shapeof the crucibles 80 a, 80 b while rotating the chill block 204.Accordingly, no directivity occurs during the cooling of the moltenmetal 84 in the crucibles 80 a, 80 b. It is possible to quickly obtainthe desired semisolidified metal 90 formed into the slurry uniformly andreliably as a whole. Therefore, it is unnecessary to reheat thesemisolidified metal 90. The semisolidified metal 90 can be directlysupplied to the slurry-introducing port 24 of the forming machine 22.

Accordingly, the following effects are obtained. That is, it is possibleto always obtain the stable semisolidified metal 90 for every one shot.Further, it is unnecessary to provide the equipment such as thereheating unit, and it is possible to produce the semisolidified metal90 economically and efficiently. The external shape of the chill block204 is designed to have the quadratic prism-shaped configuration.Therefore, it is possible to reliably agitate the molten metal 84. Thechill block 204 has the draft formed downwardly. Thus, the chill block204 can be smoothly withdrawn from the semisolidified metal 90.

FIG. 19 shows an illustrative schematic perspective view depicting anagitator 290 which constructs a production apparatus for carrying out amethod for producing semisolidified metal according to the fifthembodiment of the present invention.

The agitator 290 is provided with a pair of chill blocks (coolingmembers) 296 a, 296 b for cooling and agitating molten metal 294 individed type crucibles 292 a, 292 b. The chill blocks 296 a, 296 b arearranged detachably with respect to rotary sections 298 a, 298 a withcouplers 300 a, 300 b made of ceramics intervening therebetween. Thechill blocks 296 a, 296 b are made of, for example, copper or stainlesssteel, in the same manner as the chill block 204. The chill blocks 296a, 296 b are designed to have a quadratic prism-shaped external shape,and they have a draft formed downwardly.

The rotary sections 298 a, 298 b rotate and drive the chill blocks 296a, 296 b. On the other hand, the rotary sections 298 a, 298 b aremovable upwardly and downwardly in an integrated manner together withthe chill blocks 296 a, 296 b by the aid of a moving section 302, andthey make reciprocating movement in the horizontal direction along thelongitudinal direction (direction of the arrow A) of the crucibles 292a, 292 b. That is, the moving section 302 has two functions of anelevator means and a horizontally moving means.

The crucibles 292 a, 292 b are designed to have a rectangularconfiguration in a state of making tight contact with each other. Aheat-resistant packing 304 is interposed between their joining surfaces.The crucibles 292 a, 292 b are arranged on unillustrated divided typecrucible holders. An integrated type crucible may be adopted in place ofthe divided type crucibles 292 a, 292 b.

In the fifth embodiment constructed as described above, the molten metal294 in an amount of one shot is firstly fed into the inside of thecrucibles 292 a, 292 b which are allowed to make tight contact with eachother. After that, the chill blocks 296 a, 296 b are arranged atpositions over the crucibles 292 a, 292 b by the aid of the movingsection 302. Subsequently, the chill blocks 296 a, 296 b are moveddownwardly while being rotated in accordance with the action of therotary sections 298 a, 298 b.

The chill blocks 296 a, 296 b are moved in a reciprocating manner in thehorizontal direction in accordance with the action of the moving section302, after the chill blocks 296 a, 296 b are immersed in the moltenmetal 294 in the crucibles 292 a, 292 b, or simultaneously with therotary driving. Accordingly, the chill blocks 296 a, 296 b cool themolten metal 294 in the crucibles 292 a, 292 b, and they agitate themolten metal 294 along the shape of the crucibles 292 a, 292 b.

As described above, in the fifth embodiment, the chill blocks 296 a, 296b make the reciprocating movement along the longitudinal direction(direction of the arrow A) of the crucibles 292 a, 292 b while beingrotated. Accordingly, the molten metal 294 can be agitated reliably andeffectively over the entire interior of the crucibles 292 a, 292 b.Therefore, the same effects as those obtained in the fourth embodimentare obtained, for example, such that it is possible to obtain thedesired semisolidified metal 90 in the satisfactory slurry state whichis uniform as a whole and which has no directivity of cooling, in thecrucibles 292 a, 292 b.

FIG. 20 shows an illustrative schematic perspective view depicting anagitator 320 which constructs a production apparatus for carrying out amethod for producing semisolidified metal according to the sixthembodiment of the present invention.

The agitator 320 is provided with a chill block (cooling member) 326 forcooling and agitating molten metal 324 in divided type crucibles 322 a,322 b. The chill block 326 is arranged detachably with respect to a,rotary section 328 with a coupler 330 made of ceramics interveningtherebetween. The chill block 326 is made of, for example, copper orstainless steel, in the same manner as the chill block 204 describedabove. The chill block 326 is designed to have a quadratic prism-shapedexternal shape, and it has a draft formed downwardly.

A rotary section 328 rotates and drives the chill block 326. On theother hand, the rotary section 328 is movable upwardly and downwardly inan integrated manner together with the chill block 326 by the aid of amoving section 332. That is, the moving section 332 has a function toserve as a vertically moving means for making reciprocating movement ofthe chill block 326 in the longitudinal direction (direction of thearrow B) of the crucibles 322 a, 322 b.

The crucibles 322 a, 322 b are designed to have a cylindricalconfiguration in a state of making tight contact with each other. Aheat-resistant packing 334 is interposed between their joining surfaces.The crucibles 322 a, 322 b are arranged on unillustrated divided typecrucible holders. An integrated type crucible may be adopted in place ofthe divided type crucibles 322 a, 322 b.

In the sixth embodiment constructed as described above, the molten metal324 in an amount of one shot is firstly fed into the inside of thecrucibles 322 a, 322 b which are allowed to make tight contact with eachother. After that, the chill block 326 is arranged at a position overthe crucibles 322 a, 322 b by the aid of the moving mechanism 332.

Subsequently, the chill block 326 is moved downwardly by the aid of themoving section 332 while being rotated in accordance with the action ofthe rotary section 328. The chill block 326 is immersed in the moltenmetal 324 in the crucibles 322 a, 322 b, and then it makes reciprocatingmovement in the vertical direction in accordance with the action of themoving section 332. Accordingly, the chill block 326 cools the moltenmetal 324 in the crucibles 322 a, 322 b, and it agitates the moltenmetal 324 along the shape of the crucibles 322 a, 322 b.

As described above, in the sixth embodiment, the chill block 326 makesthe reciprocating movement in the longitudinal direction (direction ofthe arrow B) of the crucibles 322 a, 322 b while being rotated.Accordingly, the molten metal 324 can be agitated reliably andeffectively over the entire interior of the crucibles 322 a, 322 b.Therefore, the same effects as those obtained in the fourth and fifthembodiments are obtained, for example, such that it is possible toobtain the desired semisolidified metal 90 in the satisfactory slurrystate which is uniform as a whole and which has no directivity ofcooling.

In the fourth to sixth embodiments, each of the chill blocks 204, 296 a,296 b, 326 is designed to have the rectangular configuration. However,there is no limitation thereto. For example, it is also allowable to usea chill block 340 designed to have an external shape of an ellipticalconfiguration (see FIG. 21), a chill block 342 designed to have anexternal shape of a composite elliptical configuration (see FIG. 22), achill block 344 designed to have an external shape of a chamferedrectangular configuration (see FIG. 23), a chill block 346 designed tohave an external shape of a hexagonal configuration (see FIG. 24), and achill block 346 designed to have an external shape of chamferedhexagonal configuration (see FIG. 25).

FIG. 26 shows an illustrative schematic perspective view depicting anapparatus 400 for producing semisolidified metal according to theseventh embodiment of the present invention. The same constitutivecomponents as those of the production apparatus 200 according to thefourth embodiment shown in FIG. 16 are designated by the same referencenumerals, detailed explanation of which will be omitted.

The production apparatus 400 is provided with an agitator 402. Aplurality of chill blocks (cooling members) 406 a to 406 d, whichconstruct the agitator 402, are detachably connected to a rotary section206 with a coupler 208 made of ceramics intervening therebetween, at aposition over crucible holders 82 a, 82 b. The chill blocks 406 a to 406d are composed of, for example, a material such as copper and stainlesssteel which is not melted at a melting temperature of aluminum moltenmetal to be used as the molten metal 84. As shown in FIGS. 26 to 28, theexternal shape of the entire chill blocks 406 a to 406 d is designed tohave a quadratic prism-shaped configuration, with a draft formeddownwardly.

As shown in FIG. 28, through-holes 408 a to 408 d are formed atrespective central portions of the chill blocks 406 a to 406 d. Anarbitrary number of the chill blocks 406 a to 406 d can be held in anintegrated manner with respect to the rotary section 206 by the aid of afixing means 412. The fixing means 412 includes a screw shaft (shaftmember) 414 for being integrally inserted into the through-holes 408 ato 408 d of the stacked chill blocks 406 a to 406 d, a nut member(fixture) 416 for being screwed on the lower end of the screw shaft 414,and a support plate 415 for supporting the chill blocks 406 a to 406 d.The upper end of the screw shaft 414 can be detachably connected to thecoupler 208.

In the case of the production apparatus 400 constructed as describedabove, when the weight of the molten metal 84 in the amount of one shotis changed depending on the change of the part to be formed, the numberof chill blocks 406 a to 406 d installed to the rotary section 206 isincreased or decreased. Specifically, when the weight of the moltenmetal 84 in the amount of one shot is decreased, the chill blocks 406 ato 406 d are decreased, for example, to the chill blocks 406 a to 406 c.On the other hand, when the weight of the molten metal 84 in the amountof one shot is increased, a predetermined number of chill blocks (notshown) may be stacked on the chill blocks 406 a to 406 d.

As described above, in the seventh embodiment, the molten metal 84 inthe crucibles 80 a, 80 b is cooled with the predetermined number ofchill blocks 406 a to 406 d, and the chill blocks 406 a to 406 d arerotated in an integrated manner by the aid of the rotary section 206 toagitate the molten metal 84. Accordingly, the following effects areobtained. That is, no directivity occurs during the cooling of themolten metal 84 in the crucibles 80 a, 80 b. It is possible to extremelyquickly and efficiently obtain the desired semisolidified metal 22formed into the slurry uniformly and reliably as a whole.

Further, when the weight of the molten metal 84 in the amount of oneshot is changed, it is enough that the number of chill blocks 406 a to406 d is increased or decreased depending on the weight of the moltenmetal 84. It is possible to efficiently and highly accurately producethe semisolidified metal 90 for forming a variety of different parts.Accordingly, the following advantages are obtained. That is, it isunnecessary to prepare any exclusive cooling means corresponding to thechange of the weight of the molten metal 84. It is possible toeffectively reduce the equipment cost.

FIG. 29 shows an illustrative schematic perspective view depicting anapparatus 490 for producing semisolidified metal according to the eighthembodiment of the present invention. The same constitutive components asthose of the production apparatus 400 according to the seventhembodiment are designated by the same reference numerals, detailedexplanation of which will be omitted.

The production apparatus 490 includes a plurality of chill blocks(cooling members) 492 a to 492 d which also possess the agitatingfunction. The chill blocks 492 a to 492 d are detachably arranged withrespect to the driving mechanism 494 with a coupler 496 made of ceramicsintervening therebetween. The chill blocks 492 a to 492 d are made of,for example, copper or stainless steel, and their upper ends areintegrated into one unit with a connecting section 498. The connectingsection 498 is detachable with respect to the coupler 496. The externalshape of each of the chill blocks 492 a to 492 d is designed to have acolumnar configuration, and each of the chill blocks 492 a to 492 d hasa draft formed downwardly.

In the eighth embodiment constructed as described above, the moltenmetal 84 in an amount of one shot is fed into the crucibles 80 a, 80 b.After that, the chill blocks 492 a to 492 d are moved downwardly whilebeing rotated by the aid of the driving mechanism 494, and they areimmersed in the molten metal 84 in the crucibles 80 a, 80 b.Accordingly, the molten metal 84 in the crucibles 80 a, 80 b is cooledand agitated to obtain the semisolidified metal 90 having a desiredslurry state.

Accordingly, in the eighth embodiment, the four chill blocks 492 a to492 d are operated in an integrated manner to agitate the molten metal84 while cooling the molten metal 84 in the crucibles 80 a, 80 b.Therefore, even when the weight of the molten metal 84 is especiallylarge, an effect is obtained such that the desired semisolidified metal90 can be obtained efficiently and quickly.

FIG. 30 illustrates a chill block 500 which constructs an apparatus forproducing semisolidified metal according to the ninth embodiment of thepresent invention.

The chill block 500 is provided with a plurality of rib sections 504 ato 504 i which are integrally formed on the outer circumference of acolumnar section 502 while being separated from each other bypredetermined spacing distances in the axial direction. Therefore, inthe ninth embodiment, when the chill block 500 is rotated in the moltenmetal 84, the molten metal 84 is cooled and agitated quickly andsmoothly by the aid of the plurality of rib sections 504 a to 504 i.Thus, it is possible to obtain the same effects as those obtained in theseventh and eighth embodiments.

FIG. 31 shows an illustrative schematic view, with partial crosssection, depicting an apparatus 510 for producing semisolidified metalaccording to the tenth embodiment of the present invention.

The production apparatus 510 comprises a heat-insulating crucible 514for holding molten metal 512 composed of melted metal in a predeterminedamount (amount of one shot); a coil-shaped cooling member 516 forcooling the molten metal 512 in the crucible 514 to a predeterminedtemperature; a cooling mechanism 520 for supplying, to the inside of thecooling member 516, first liquid metal 518 as a cooling mediummaintained at a temperature which is not more than the temperature ofthe molten metal 512; and an electromagnetic agitation mechanism(driving mechanism) 522 for agitating the molten metal 512 by the aid ofthe cooling member 516.

The crucible 514 is made of, for example, silicon nitride. The crucible514 is arranged on an elevator base 524. A heating heater 526 isinstalled to the outer circumference of the crucible 514. The elevatorbase 524 is movable upwardly and downwardly by the aid of anunillustrated driving means, and it is designed to be rotatable, ifnecessary. A coil section 528, which constructs the electromagneticagitation mechanism 522, is arranged to surround the crucible 514 in thevicinity of the elevator base 524.

The cooling mechanism 520 includes a first supply means 530 forsupplying first liquid metal 518 into the cooling member 516 in order tocool the molten metal 512 to a predetermined temperature, and a secondsupply means 534 for supplying, into the cooling member 516, secondliquid metal 532 which is a heating medium having a temperature higherthan a liquefying temperature of solidified matters in order to removethe solidified matters adhered to the surface of the cooling member 516.The molten metal 512 is melted metal composed of, for example, aluminum,alloy thereof, magnesium, or alloy thereof. The first and second liquidmetals 518, 532 are stannum or stannum alloy.

The first supply means 530 includes a first storage tank 536 for storingthe first liquid metal 518; a first heating furnace (first heatingsection) 538 for keeping the temperature of the first liquid metal 518in the first storage tank 536; a heat exchanger 540 for cooling thefirst liquid metal 518 by performing heat exchange with respect to thefirst liquid metal 518; and a first circulating passage 542 forcirculating the first liquid metal 518 through the inside of the coolingmember 516.

The heat exchanger 540 is provided with a heat exchange coil 544 forsupplying cooling water thereinto. The heat exchange coil 544 isimmersed in the first liquid metal 518 in the first storage tank 536.The first heating furnace 538 is arranged to circumscribe the firststorage tank 536. The first circulating passage 542 is composed of apipe made of SUS. An inlet end 542 a thereof is connected to a lower endside of the first storage tank 536. An outlet end 542 b thereof isimmersed at a predetermined height position in the first liquid metal518 at an upward portion of the first storage tank 536. As shown in FIG.32, the first circulating passage 542 constitutes a part of the coolingmember 516. A first electromagnetic pump 546 is arranged on the side ofthe end 542 a (see FIG. 31).

The second supply means 534 includes a second storage tank 548 forstoring the second liquid metal 532; a second heating furnace (secondheating section) 550 for heating the second liquid metal 532 in thesecond storage tank 548; and a second circulating passage 552 forcirculating the cooling member 532 through the inside of the coolingmember 516.

The second heating furnace 550 is arranged to circumscribe the secondstorage tank 548. The second circulating passage 552 has its inlet end552 a which is joined to the lower side of the second storage tank 548,and its outlet end 552 b which is immersed at a predetermined positionin the second liquid metal 532 at an upper portion of the second storagetank 548. A second electromagnetic pump 554 is provided for the secondcirculating passage 552 in the vicinity of the side of the end 552 a.The second circulating passage 552 is joined with the first circulatingpassage 542 at its intermediate portion to constitute a part of thecooling member 516 (see FIG. 32).

A first thermocouple (first detecting means) 558 for measuring thetemperature of the molten metal is installed at the joined portion ofthe first and second circulating passages 542, 552 by the aid of asupport member 556. The first thermocouple 558 detects the temperatureof the molten metal 512 in the crucible 514. A second thermocouple(second detecting means) 560 for detecting the temperature of the firstliquid metal 518 is arranged for the first storage tank 536 whichconstructs the first supply means 530. On the other hand, a thirdthermocouple (third detecting means) 562 for detecting the temperatureof the second liquid metal 532 is arranged for the second storage tank548 which constructs the second supply means 534.

Explanation will be made below for the operation of the productionapparatus 510 according to the tenth embodiment constructed as describedabove.

At first, the operation is performed as shown in FIG. 33A. That is, forexample, the molten metal 512 of aluminum alloy (AC2B), which is used asa material for the molten metal, is held at a temperature of 650° C. inan unillustrated molten metal-holding furnace. A feeder 564 ladles themolten metal 512 in an amount of one shot, for example, in an amount of20 kg to be fed to the crucible 514. The heater 526 is installed to thecrucible 514. The temperature of the molten metal 512 in the crucible514 is maintained to be constant by the aid of the heater 526.

Subsequently, as shown in FIG. 33B, the elevator base 524, on which thecrucible 514 is placed, is moved upwardly. The cooling member 516 isimmersed in the molten metal 512 in the crucible 514. The cooling member516 is a pipe made of SUS having an inner diameter of 20 mm, which isconstructed to have a coil-shaped configuration with an entire length of700 mm.

On the other hand, in the cooling mechanism 520, as shown in FIG. 31,the first liquid metal 518 is maintained at 250° C., and it is stored inan amount of 100 liters in the first storage tank 536 which constitutesthe first supply means 530. The second liquid metal 532 is maintained at600° C., and it is stored in an amount of 40 liters in the secondstorage tank 548 which constitutes the second supply means 534. Thetemperatures of the first and second liquid metals 518, 532 are detectedby the second and third thermocouples 560, 562 respectively. The heatexchanger 540 and the first heating furnace 538 are operated on thebasis of the result of the detection performed by the secondthermocouple 560. Thus, the temperature of the first liquid metal 518 ismaintained to be constant. On the other hand, the second heating furnace550 is operated on the basis of the result of the detection performed bythe third thermocouple 562. Thus, the temperature of the second liquidmetal 532 is maintained to be constant.

The first electromagnetic pump 546 is operated so that the first liquidmetal 518 in the first storage tank 536 is introduced into the inside ofthe cooling member 516 via the first circulating passage 542 at a flowrate of 20 liters/minute. After that, the first liquid metal 518 isreturned from the end 542 b to the inside of the first storage tank 536(see FIG. 33C). Accordingly, the molten metal 512 in the crucible 514 iscooled by the aid of the cooling member 516 in which the first liquidmetal 518 having the relatively low temperature is circulated throughthe inside. During this process, the coil section 528, which constitutesthe electromagnetic agitation mechanism 522, is operated to agitate themolten metal 512 in the crucible 514.

The temperature of the molten metal 512 in the crucible 514 is detectedby the first thermocouple 558. The cooling and the agitation areperformed for the molten metal 512 until the detected temperaturearrives at the preset semisolidification temperature. Therefore, thesemisolidified metal 566, which has no directivity of cooling and whichis formed into the slurry uniformly and successfully as a whole, isproduced in the crucible 514 (see FIGS. 31 and 33C).

Subsequently, the operation of the first electromagnetic pump 546 isstopped, and the second electromagnetic pump 554 is operated.Accordingly, as shown in FIG. 33D, the liquid metal 532 in the secondstorage tank 548 is supplied to the inside of the cooling member 516 viathe second circulating passage 552 at a flow rate of 20 liters/minute.The second liquid metal 532 is held at a temperature higher than theliquefaction temperature of the aluminum alloy used for the molten metal512. Even when aluminum solidified matters adhere to the surface of thecooling member 516, the aluminum solidified matters can be dissolvedagain to reliably remove them. After that, the operation of the secondelectromagnetic pump 554 is stopped, and the elevator base 524 is moveddownwardly to separate the crucible 514 from the cooling member 516.

Accordingly, the desired semisolidified metal 566 is obtained in thecrucible 514. During this process, the first and second liquid metals518, 532 are supplied to the cooling member 516 at the flow rate of 20liters/minute by the aid of the first and second electromagnetic pumps546, 554. Therefore, the molten metal 512 in the crucible 514 is cooledfrom 650° C. to the slurry temperature of 570° C. for about 1 minute. Onthe other hand, it is possible to effectively prevent the surface of thecooling member 516 from adhesion of aluminum solidified matters.

In the tenth embodiment, the first liquid metal 518, which is maintainedat the predetermined cooling temperature, is supplied in the circulatingmanner to the inside of the cooling member 516 to cool the molten metal512 in the state in which the cooling member 516 is immersed in themolten metal 512 in the crucible 514. Further, the electromagneticagitation mechanism 522 is operated to agitate the molten metal 512.Accordingly, no directivity occurs during the cooling of the moltenmetal 512. It is possible to obtain the semisolidified metal 566 formedinto the slurry uniformly and reliably as a whole.

The first and second thermocouples 558, 560 are used to detect thetemperatures of the molten metal 512 and the first liquid metal 518 sothat the temperature of the first liquid metal 518 is managed.Accordingly, it is unnecessary to reheat the semisolidified metal 566.Such an effect is obtained that the semisolidified metal 566 having ahigh quality can be efficiently obtained. Especially, it is advantageousthat the temperature of the semisolidified metal 566 is managed easilyand correctly, and the cooling speed for the molten metal 512 isimproved so that the semisolidified metal 566 may be quickly producedall at once.

The tenth embodiment is provided with the second supply means 534 forsupplying, to the inside of the cooling member 516, the second liquidmetal 532 having the temperature higher than the liquefactiontemperature of the molten metal material (for example, aluminum alloy)after the semisolidified metal 566 is produced. That is, it is fearedthat the aluminum solidified matters formed by the solidification of themolten metal 512 adhere to the surface of the cooling member 516 afterperforming the cooling and the agitation for the molten metal 512,resulting in formation of any solidified layer. If the solidified layerhas a thick wall thickness, then it is feared that the aluminumsolidified matters are oxidized to cause contamination into the moltenmetal 512 in the crucible 514 upon the next time shot, or the aluminumsolidified matters cause the change of the cooling condition of themolten metal 512 and the dispersion of the amount of the molten metal.

In the tenth embodiment, the second liquid metal 532 having therelatively high temperature is supplied to the second circulatingpassage 552. Therefore, the aluminum solidified matters, which adhere tothe surface of the cooling member 516, are dissolved again, and they arereliably removed from the surface. Accordingly, it is possible toefficiently obtain the semisolidified metal 566 having the high quality,and it is possible to stabilize the cooling condition.

In the tenth embodiment, the cooling member 516 is designed to have thecoil-shaped configuration in which the first and second circulatingpassages 542, 552 are joined to one another in the integrated manner.However, the cooling member 516 may be designed to have variousconfigurations such as a plate-shaped configuration, for example,corresponding to the volume and the shape of the crucible 514. That is,the cooling member 516 may be designed to have an optimum configurationso that the surface area is increased.

The electromagnetic agitation mechanism 522 is used to agitate themolten metal 512. However, in place thereof, it is possible to adopt amechanical agitation structure. For example, the molten metal 512 may beagitated by rotating the crucible 514 itself, or by moving the crucible514 in the horizontal direction together with the rotation of thecrucible 514. Further, the following arrangement is also available. Thatis, the cooling member 516 itself may be rotated, or it may be designedto be movable in the horizontal direction.

INDUSTRIAL APPLICABILITY

As described above, in the present invention, the molten metal, which issupplied to the heat-insulating crucible, is agitated while being cooledby the aid of the cooling member. Therefore, the molten metal is formedinto the slurry in the crucible uniformly and reliably as a whole. It ispossible to easily and efficiently obtain the desired semisolidifiedmetal having no directivity of cooling. Further, it is unnecessary toreheat the semisolidified metal. It is possible to reliably avoid theexpensive equipment cost.

In the present invention, the molten metal in the crucible is cooled bythe aid of the cooling member, and the molten metal is agitated bymoving the cooling member along the shape of the crucible. Accordingly,the molten metal is formed into the slurry in the heat-insulatingcrucible uniformly and reliably as a whole. It is possible to easily andefficiently obtain the desired semisolidified metal having nodirectivity of cooling.

In the present invention, the molten metal in the crucible is cooled andagitated by the aid of the plurality of cooling members. Therefore, thedirectivity of cooling is excluded to be as less as possible, and it ispossible to quickly and efficiently produce the desired semisolidifiedmetal formed into the slurry uniformly and reliably as a whole.

In the present invention, the cooling member is immersed in the moltenmetal in the heat-insulating crucible. The molten metal is agitated inthe state in which the cooling medium is supplied to the inside of thecooling member. Accordingly, no directivity occurs during the cooling ofthe molten metal, and it is possible to form the slurry of the moltenmetal quickly and reliably. Further, the desired semisolidified metalcan be obtained efficiently and highly accurately by managing thetemperature of the cooling medium.

In the present invention, the molten metal, which is contained in thedivided type heat-insulating crucibles, is cooled and agitated by theaid of the cooling member to produce the semisolidified metal. Afterthat, the heat-insulating crucibles are subjected to the opening/closingoperation by the aid of the opening/closing mechanism. Accordingly, thesemisolidified metal in the heat-insulating crucibles falls from theheat-insulating crucibles due to its own weight, and it is dischargedtherefrom. Accordingly, the directivity of cooling is excluded to be asless as possible, and it is possible to obtain the desiredsemisolidified metal formed into the slurry uniformly and reliably as awhole. Further, it is possible to discharge the semisolidified metalfrom the heat-insulating crucibles smoothly and reliably by using thesimple structure.

What is claimed is:
 1. A method for producing semisolidified metal,comprising the steps of: supplying a predetermined amount of moltenmetal to a heat-insulating non-cooled crucible; cooling said moltenmetal in said heat-insulating crucible by the aid of a cooling memberused as an agitator, said cooling member being cooled to a predeterminedtemperature which is not more than a temperature of said molten metal,and agitating said molten metal; agitating said molten metal by usingsaid cooling member; completing said agitation step after agitating saidmolten metal to give a predetermined slurry state; withdrawing saidcooling member to a position outside of said heat-insulating crucible;subjecting said cooling member to a temperature control process in acooling member treating unit; removing solidified matters adhered to asurface of said cooling member after withdrawing said cooling memberfrom said heat-insulating crucible; costing said cooling member with aceramic material after removing said solidified matters; and applying adrying treatment to said cooling member after coating said coolingmember with said ceramic material prior to moving the cooling member toa position inside the heat-insulating crucible.
 2. A method forproducing semisolidified metal, comprising the steps of: supplying apredetermined amount of molten metal to a heat-insulating crucible;cooling said molten metal in said heat-insulating crucible by the aid ofa cooling member cooled to a predetermined temperature which is not morethan a temperature of said molten metal, said cooling member beingdisplaceable from a position outside of said heat-insulating crucible toa position inside said heat-insulating crucible; agitating said moltenmetal by moving said cooling member in a horizontal direction and/or ina vertical direction while rotating said cooling member; completing saidagitation step after agitating said molten metal to give a predeterminedslurry state; withdrawing said cooling member to said position outsideof said heat-insulating crucible; and tilting said crucible so that saidmolten metal in said predetermined slurry state falls into a formingunit, wherein the step of supplying the predetermined amount of moltenmetal to a heat-insulating crucible is performed concurrently with thestep of agitating said molten metal in at least two otherheat-insulating crucible.
 3. The method for producing saidsemisolidified metal according to claim 1, wherein an external shape ofsaid cooling member is set to have a columnar configuration with a draftformed downwardly.
 4. The method for producing said semisolidified metalaccording to claim 1, wherein an external shape of said cooling memberis set to have a prism configuration with a draft formed downwardly. 5.The method for producing said semisolidified metal according to claim 1or 2, wherein said cooling member is inserted into said heat-insulatingcrucible, and an open end of said heat-insulating crucible is closed bya lid member.
 6. The method for producing said semisolidified metalaccording to claim 1 or 2, wherein a plurality of cooling members areprovided.
 7. An apparatus for producing semisolidified metal,comprising: a heat-insulating crucible for holding predetermined amountof molten metal; a cooling member for agitating and cooling said moltenmetal in said heat-insulating crucible to a predetermined temperature;means for displacing said cooling member from a position outside of saidheat-insulating crucible to a position inside said heat-insulatingcrucible; a driving mechanism for agitating said molten metal byrotating said cooling member; first temperature control means forcontrolling temperature of said cooling member after displacing saidcooling member to said position outside said heat-insulating crucible;air blow means for removing semi solidified metal from the coolingmember; coasting means for applying a coat of ceramic material to asurface of the cooling member; and drying mean for subjecting thecooling member to a drying treatment prior to displacing the coolingmember to said position inside the heat-insulating crucible.
 8. Theapparatus for producing said semisolidified metal according to claim 7,wherein an external shape of said cooling member is set to have acolumnar configuration with a draft formed downwardly.
 9. An apparatusfor producing semisolidified metal, comprising: means for successivelysupplying a predetermined amount of molten metal into each of aplurality of heat-insulating crucibles; a cooling member for each ofsaid heat-insulating crucibles for agitating and cooling said moltenmetal to a predetermined temperature; means for displacing said coolingmembers from a positions outside of said heat-insulating crucibles topositions inside said heat-insulating crucibles; a driving mechanism foragitating said molten metal by moving said cooling members in ahorizontal direction and/or in a vertical direction while rotating saidcooling member; wherein the means for supplying molten metal to one ofthe heat-insulating crucible operates concurrently with the agitatingand cooling operation of the cooling members of at least two others ofthe heat-insulating crucibles.
 10. The apparatus for producing saidsemisolidified metal according to claim 9, wherein said drivingmechanism includes a horizontal moving means for making reciprocatingmovement of said cooling members in said horizontal direction.
 11. Theapparatus for producing said semisolidified metal according to claim 9,wherein said driving mechanism includes a spiral moving means for makingspiral movement of said cooling members in said horizontal direction.12. The apparatus for producing said semisolidified metal according toclaim 9, wherein said driving mechanism includes a vertical moving meansfor making reciprocating movement of said cooling members in saidvertical direction.
 13. The apparatus for producing said semisolidifiedmetal according to claim 9, wherein an external shape of each of thesaid cooling members is set to have a prism configuration with a draftformed downwardly.